This invention relates to a method of production of compositions containing synthetic resins or elastomers, which will not shrink or which will increase in volume during setting.
Compositions of said type find application in building engineering as joints, self-tensioning structural elements, sealants etc., as well as in electrical engineering as insulating materials, and in other fields of technology as for instance shock-absorbing inserts.
Chemically setting and thermosetting compounds commonly used are characterized by a reduction in volume during the setting process. The amount of said shrinkage for non-filled compounds extends from 0.5% in the case of epoxy resins even up to 12% for polyester resins. Negative consequences of such a shrinkage consist in stresses generated within the material, causing under certain circumstances the destruction of said material.
Shrinkage during setting of a synthetic material frequently causes, for instance, breakaways of the lining from the cement base, difficulties with lifting of the pattern of some prefabricated units and also makes it impossible to obtain tight joints.
Known building materials which increase their volume are concretes based upon expanding cements. Their relatively low degree of expansion, lack of chemical corrosion resistance and of scratch resistance notably restrict the application possibilities thereof.
Other known materials of the discussed type, as for instance polyurethane foams, although they show satisfactory chemical resistance, provide no properties suitable for a structural material.